In a wireless communication system, both uplink and downlink communication for each User Equipment (UE) is supported by a base station. In a downlink direction, data is transmitted from the base station to which the UE has accessed to the UE through a downlink physical channel, and then demodulated by the UE.
There exists a plurality of base stations in a wireless communication network, and the downlink data transmission may be performed by different base stations using an identical frequency resource at an identical time point. In the case that the data is transmitted from the base station to the UEs within a cell where the base station is located, a resultant downlink transmission signal may occupy a time-domain resource and a frequency-domain resource identical to a downlink signal from the other base stations. Hence, the downlink data transmission from one base station to one UE may probably interfere with the downlink data transmission from another base station to another UE. In other words, in the case that the base station transmits different signals to a first UE and a second UE as target reception devices and the signal transmitted to the second UE does not include the signal transmitted to the first UE, the signal transmitted to the second UE may interfere with the first UE.
An intensity of an interference signal depends on various factors, including a size of the cell and transmission power. In the case that the intensity of the interference signal is great enough with respect to an intensity of a target data signal, an intensive interference may occur, and thereby demodulation performance of the target data may be adversely affected.
Interference is a principal performance restraint factor for a wireless cellular communication system, and it includes intra-cell interference and inter-cell interference. The inter-cell interference is generated in the case that a base station in an adjacent cell also schedules the data for the other UEs in the adjacent cell at an identical frequency. The UEs at an edge of the cell may be greatly adversely affected by the intra-cell interference.
The intra-cell interference is generated mainly in the case that a base station (evolved NodeB (eNB)) may transmit data to different UEs on an identical time-domain/frequency-domain resource. Identical or different beamforming matrices are adopted by the different UEs, and a multiple access operation may be achieved by differentiating the UEs in a space domain or the others. In the case that spatial channels are differentiated from each other in a better manner, different beamforming matrices may be adopted by two UEs. In the case that a beamforming matrix for one UE is orthogonal to a signal transmitted to the other UE in a better manner, it is able to reduce, to some extent, the intra-cell interference. In a Long Term Evolution (LTE) system, a conventional downlink Multiuser Multiple Input Multiple Output (MU-MIMO) technology is just based on this mode.
In addition, the MU-MIMO technology may be implemented through power or spreading code, i.e., different UEs may be configured with different power or spreading codes/sequences. The interference between the UEs may be cancelled out through an advanced receiver.
In a conventional communication technology, one target reception device may merely demodulate the data transmitted thereto, and it may not demodulate, or perform elimination/suppression treatment on, the data transmitted from a network to the other reception devices, i.e., the interference signal received by the target reception device. Here, the reception device is any UE which is capable of receiving the signal from a network device (e.g., the base station).
Along with the development of the technology, the advanced receiver has been gradually used in the communication system. As compared with a conventional receiver, the advanced receiver may be used to jointly process the signal transmitted to the target reception device and the signal transmitted to an interference UE (i.e., the interference signal received by the target reception device), and perform such treatment as elimination, suppression and cancellation on the interference signal, to improve the reception performance of the target reception device.
In a wireless communication system, the intra-cell interference may be eliminated through the advanced receiver. In order to eliminate the intra-cell interference (i.e., the interference between different UEs), it is necessary to acquire parameters of the interference signal. These parameters may be acquired through blind detection on the reception device, but the acquisition procedure is very complex.
In the conventional LTE system, dynamic downlink control signaling transmitted from the network to the UE is called as Downlink Control Information (DCI). The DCI includes transmission parameter information configured by the network for scheduling the UE to perform the data reception, e.g., a frequency band on which the data transmission is performed, a demodulator order of the data (Quadrature Phase Shift Keying (QPSK)/16-Quadrature Amplitude Modulation (QAM)/64-QAM), a transport block size (TBS), and so on. The DCI is transmitted through an air interface over a Physical Downlink Control Channel (PDCCH), and then the UE may detect the PDCCH in a blind mode to acquire its own DCI.
The DCI transmitted from the network device to one target reception device may merely include the transmission parameter information for the data reception with respect to the target reception device. In the case that a UE A is the target reception device, the DCI (i.e., DCI A) transmitted to the UE A may merely include the transmission parameter information (i.e., ControlInfo-Self, which includes X bits) for the data reception with respect to the UE A. The UE may also be configured by the network to receive transmission parameter information from a UE B (i.e., DCI B including ControlInfo-Interf). However, the interference elimination may be performed dynamically using ControlInfo-Interf within one subframe. In other words, the network side device may always transmit the transmission parameter information of the interference signal (i.e., ControlInfo-Interf) to the target UE A, and the UE A needs to perform the interference elimination using ControlInfo-Interf sometimes while it may not perform the interference elimination using ControlInfo-Interf sometimes. In addition, a Modulation and Coding Scheme (MCS) scheduled by the network is also directly related to an expected Signal-to-Noise Ratio (SNR), and the SRN for the interference elimination may be greatly different from that not for the interference elimination. In the case that the network has scheduled a large MAS for the UE but the UE does not perform any interference elimination, the data may probably not be received by the UE accurately, so the system performance may be seriously adversely affected. In the case that the network has scheduled a low MCS for the UE, it is impossible for the UE to acquire a desired data rate, and thereby the system performance may also be adversely affected.
In the related art, the reception device acquires, through blind detection, the transmission parameter information for receiving the data, but it is impossible for the reception device to eliminate the interference signal received thereby. Even in the case that the reception device is configured to receive the transmission parameter information about a signal from the interference UE, the reception device may perform the interference elimination dynamically using the transmission parameter information about the signal from the interference UE. Hence, it is impossible for the reception device to match the MCS scheduled by the network, and thereby the data rate of the reception device as well as the system performance may be adversely affected.